Field Induced Jet Micro-EDM

Electrical discharge machining (EDM) is of the potential of micro/nano meter scale machining capability. However, electrode wear in micro-EDM significantly deteriorates the machining accuracy, thus, it needs to be compensated in process. To solve this problem, a novel micromachining method, namely field induced jet micro-EDM, is proposed in this paper, in which the electrical field induced jet is used as the micro tool electrode. A series of experiments were carried out to investigate the feasibility of proposed method. Due to the electrolyte can be supplied automatically by the capillary effect and the electrostatic field, it is not necessary to use pump or valves. The problem of electrode wear does not exist at all in the machining process because of the field induced jet will be generated periodically. It is also found that the workpiece material can be effectively removed with a crater size of about 2 micrometer in diameter. The preliminary experimental results verified that the field induced jet micro-EDM is an effective micromachining method

Generation of Micro Mechanical Devices Using Stereo Lithography

A high resolution machining setup for creating three-dimensional precision components from a UV-curable photo-resin has been developed. By using frequency-converted diode-pumped solid state lasers, functional micro-mechanical devices are directly fabricated in a successive layer-bylayer fashion. Within this paper, the direct generation of micro assemblies having moving components without further assembly of parts will be presented. The micro system design is based on user-defined 3D-CAD data and will completively be built up within the fabrication cycle. By using specially developed μSL materials with suitable properties for micromechanical parts, the development from Rapid Prototyping towards Rapid Production of small series is intended.Mechanical Engineerin

Micro-manufacturing : research, technology outcomes and development issues

Besides continuing effort in developing MEMS-based manufacturing techniques, latest effort in Micro-manufacturing is also in Non-MEMS-based manufacturing. Research and technological development (RTD) in this field is encouraged by the increased demand on micro-components as well as promised development in the scaling down of the traditional macro-manufacturing processes for micro-length-scale manufacturing. This paper highlights some EU funded research activities in micro/nano-manufacturing, and gives examples of the latest development in micro-manufacturing methods/techniques, process chains, hybrid-processes, manufacturing equipment and supporting technologies/device, etc., which is followed by a summary of the achievements of the EU MASMICRO project. Finally, concluding remarks are given, which raise several issues concerning further development in micro-manufacturing

Laser surface texturing of a WC-CoNi cemented carbide grade: surface topography design for honing application

Abrasive effectiveness of composite-like honing stones is related to the intrinsic surface topography resulting from the cubic boron nitride (CBN) grains protruding out of the metallic matrix. Within this framework, Laser Surface Texturing (LST) is implemented for replicating topographic features of a honing stone in a WC-base cemented carbide grade, commonly employed for making tools. In doing so, regular arrays of hexagonal pyramids (similar to CBN grains) are sculpted by a laser micromachining system. Micrometric precision is attained and surface integrity does not get affected by such surface modification. Finally, potential of laser-patterned cemented carbide tools, as alternative to conventional honing stones, is supported by successful material removal and enhanced surface smoothness of a steel workpiece in the abrasive testing.Peer ReviewedPostprint (author's final draft

Micro & nano scale mechanical testing and assembly with applications to metal based microsystems

Metal-based high-aspect-ratio microscale structures (HARMS) are fundamental building blocks for functional metallic micro devices. This dissertation focuses on addressing several problems in fabrication and assembly of metal based microchannel devices. First, the materials’ responses to mechanical deformation at micro & nano scales, namely the mechanical “size effect”, have been explored by molding single crystal Al with long rectangular diamond punches and long wedge shaped indenters. It is noticed that the contact pressure of rectangular punches pressed into single crystal Al strongly depends on the punch width, while that of long wedge shaped indenters depends on the included wedge angle. We observed large discrepancies between characteristic lengths obtained from predictions based on the Nix-Gao model and those derived from experimental results. Our results suggest that the characteristic length maybe dependent on the deformation geometry. The mold inserts are coated with hard ceramic thin films, which could reduce friction and act as barriers for surface chemical reactions during molding at elevated temperatures. The adhesion between thin film and substrate, a persisting topic in thin film technologies and surface engineering, remains critical in the present case. Therefore, nominal shear strength of the interface between TiN thin film and Si substrate was evaluated through customized compression test of micro cylinders containing inclined film/substrate interfaces. Non-tapered micro cylinders with diameters ranging from 5µm to 1µm were prepared by focused ion beam “lathe milling”, which was realized by a script based ion milling program. As compared to previous procedures for testing film/substrate interfacial mechanical integrity, results obtained by following this new microscale testing protocol have less scatter and are more conducive to correlating interfacial structure/chemistry to interfacial failure. Appropriate bonding technology is critical to forming functional micro devices. Cu based HARMS were bonded by sandwiching an Al thin foil in between a Cu sheet metal containing HARMS features and a flat Cu sheet metal counterpart, utilizing formation of a eutectic interfacial liquid. Phase and structure evolution of the Cu/Al/Cu interface, as well as the interfacial mechanical properties, were characterized

Application of focused ion beam micromachining: a review

Fabrication of micro and nanoscale components are in high demand for various applications in diversified fields that include automotive, electronics, communication and medicine. Focused ion beam (FIB) machining is one of the techniques for microfabrication of micro devices. This paper presents a review of FIB machining technology that include its parameter, responses, its important component systems, as well as the fundamentals of imaging, milling (etching) and deposition techniques. The application of FIB in micromachining is also presented